Granulomatous prostatitis: a hypoechoic lesion of the prostate.

Numerous benign and malignant entities can disrupt the normal prostatic parenchymal architecture producing hypoechoic lesions in the peripheral zone. We report two cases of granulomatous prostatitis mimicking carcinoma. The differential diagnosis of hypoechoic lesions and the etiologies of granulomatous prostatitis are discussed. All hypoechoic lesions in the peripheral zones of the prostate require biopsy for histologic diagnosis.